Can you explain the advantage of putting the bullet further up in the barrel?

Some rifles actually like what is called "bullet jump". That is, the tip of the bullet starts out some distance before the rifling starts. Other rifles do better when you minimize or eliminate that distance.

One of the problems with maintaining that magical distance is that different bullet brands/shapes/weights, etc. stick out different distances. That is one reason handloaders are always playing with OAL (over all length) to find that magic spot. With a rimfire cartridge, you don't have that ability to customize the cartridge OAL. Instead, you can customize the chamber to fit the cartridges you plan to shoot.